1. Technical Field
The present invention relates generally to power tools such as rotatable drills, power screwdrivers, and rotatable cutting devices. More particularly, the present invention relates to a transmission for a multi-speed transmission for a rotary power tool.
2. Discussion
Modernly, manufacturers of power tools have introduced rotary power tools that have variable speed motors in an attempt to permit the users of these tools with sufficient control over the output speed of the tool so as to permit them to perform diverse operations without resort to additional, specialized tools. Many of the tools that are commercially available include a three-stage, two-speed transmission that permits even greater control over speeds of these tools.
Typically, the known transmission arrangements have lacked a transmission arrangement that could produce a wide range of output speeds and torques that would permit the tool to perform diverse operations such as drilling holes with a large diameter hole saw, installing drywall screws or large diameter lag screws, and performing high-speed drilling operations. The single or dual speed transmissions that were generally employed in these tools typically did not have sufficient speed reducing capacity to permit these transmissions to be diversely employed as configuring these tools for high torque operations tended to impair their high speed performance. Furthermore, the rechargeable batteries that were employed in many of the early cordless rotary power tools were not well suited for use in low-speed, high torque operations due to the amount of energy that is consumed and the rate with which the energy is consumed by the power tool during such operations. Consequently, consumers were often forced to purchase two different rotary power tools, a medium-duty tool for “standard” applications such as drilling and fastening, and a heavy-duty tool having a low-speed, high torque output for more demanding tasks.
With the advent of the modern high capacity, high voltage battery, it is now possible to meet the energy demands of a power tool that is used in low-speed, high torque operations. There remains, however, a need in the art for a power tool transmission having a relatively large range in its speed reducing capacity.